This invention relates to reed valves for use in internal combustion engines, and the invention is particularly concerned with reed valves formed of resin materials and having a coating for protecting the valves from deterioration by chemical attack and/or subjection to high temperatures. Although the reed valves of the present invention are useable in a wide variety of internal combustion engines, the valves of the present invention are particularly adapted for use in internal combustion engines operating on the two-cycle principle, especially such two-cycle engines where the engines incorporate a plurality of cylinders.
In various internal combustion engines, and particularly in multi-cylinder, two-cycle internal combustion engines, it has been noted that reed valves formed of resin materials are subjected to certain operating conditions having a tendency to deteriorate the resin material of which the reed valves are formed, especially in the marginal areas of the valve reeds where they overlie and contact the areas of the valve seat immediately surrounding the valve port. Although the tendency for deterioration may not be constantly present, there are times in the operation of an engine of the kind referred to where the tendency for deterioration becomes more pronounced. It is believed that a backfiring condition, which occurs particularly at the time of engine starting or before the normal steady state operation is established, represents a condition which accentuates the tendency for corrosive attack. In any event, it has been found that at some times in the operation of the engine, there are conditions under which certain gases tend to leak in reverse flow under the edges of the reed valves. It is possible this may occur even during normal closure of the valves and/or at times when the valve reeds are not completely closed. These conditions have been found to deteriorate the reed valve surfaces presented toward the valve seat surrounding the valve port.
It is a primary object of the present invention to provide reed valves adapted to resist deterioration even when used in engines having the deterioration tendency above referred to.